The present invention relates to casting and molding equipment, and more particularly to a mold assembly into which molten material is introduced to create an article.
Casting and molding processes are commonly used to manufacture articles from a variety of different industrial materials such as metal, plastic, and ceramic. A conventional casting or molding apparatus includes a die or mold assembly defining a cavity in the shape of the desired article and a material delivery system for introducing material into the cavity. In general, these processes involve the steps of (1) changing the material into its liquid state, (2) pouring or injecting the material into the die or mold cavity, (3) allowing the material to cure, (4) opening the die or mold assembly to provide access to the article, and (5) removing the article from the mold cavity. The die or mold assembly can be closed and the process repeated for the desired number of articles.
In view of (1) the flow characteristics of the molten material and (2) practical limitations on the capacities of molds and material-delivery systems, there are limitations on the size and shape of articles that can be cast or molded. For example, the cohesive nature of the molten material and the friction inherent in the mold cavity can make it difficult and sometimes impossible to completely fill a large or complex mold cavity using conventional pouring and injecting techniques. To overcome this shortcoming, large articles are sometimes cast in separate parts that are assembled after casting using conventional methods, such as welding, adhesives, and mechanical fasteners. The assembly steps add to the cost of manufacture, present quality control issues, and are not suitable for many large articles.